The autocomplete UI plugin has a source option to specify the suggestions to be givveb to the user. The third variation of this option is a callback function.This callback gets two arguments: a request object, with a single term property, which refers to the value currently in the text input and a

a response callback, which expects a single argument: the data to suggest to the user

How this works behind the hood?

How/When is the Object created?How/When is the response callback called?